In rotating turbomachinery, such as compressor and turbine stages of gas turbine engines, flow passages are defined by airfoil surfaces and an endwall. The airfoils are supported on platform structures that are circumferentially spaced about an engine center axis. The platform structures together form the endwall. Each platform structure is separated from an adjacent platform structure by a gap. Seals are provided at these gaps to seal the flow passages.
When defining the endwall contour shape for compressor or turbine rows that have varying platform geometries from passage to passage, typically due to strut machining, the contoured endwall shape has to vary to fit within the passage shape. Whether the endwall shape is scaled to fit the passage, or is specifically designed for each passage, a mismatch might be created at the platform gap. This mismatch is aerodynamically undesirable as it will result in an increase in loss. Also, different seals will be required to seal the gap between each combination of adjacent platforms, which increases cost.